This invention relates to the field of pedometers and in particular to pedometers using an AINS (aided inertial navigation system).
Simple Pedometer: The simple pedometer is exemplified by a hiker""s pedometer. It detects the up-down motion of the pedestrian as he takes a step, sums the number of up-down movements, and then multiplies the sum by an assumed step length. The pedestrian calibrates the pedometer by walking a measured distance and then manually entering that distance into the pedometer. The pedometer in fact maintains a simple step model for the pedestrian, and will need to be recalibrated when a different pedestrian uses the pedometer.
A complex version of a pedometer is taught in U.S. Pat. No. 5,724,265 for a xe2x80x9cSystem AND METHOD FOR MEASURING MOVEMENT OF OBJECTSxe2x80x9d issued on Mar. 3, 1998 to Lawrence J. Hutchings. This patent teaches a form of a pedometer that uses accelerometers and rotational sensors placed in the sole of a pedestrian""s shoe to measure the length of the person""s stride.
The invention Position and Orientation System for Land Survey (POS/LS) is carried by an operator or surveyor who walks a predetermined survey path while carrying the POS/LS as a backpack. The survey path or trajectory can and does often pass through areas where no GPS signals are available. The POS/LS must therefore navigate in a dead-reckoning mode with as little position drift as possible through those areas where GPS outages exist. The current method of position drift control requires the operator to perform frequent Zero Velocity Updates (ZUPD). The operator is required to maintain the POS/LS motionless for 15-30 seconds approximately every two minutes. Any alternative aiding information that limits the position drift during GPS outages can potentially improve the accuracy of the survey data generated by the POS/LS and allow operation with fewer or no ZUPD""s.